This invention relates to connector means for fuel lines of a gas turbine engine and more particularly to coupling means for concentric tubes designed to avoid leakage from either or both of said tubes.
U.S. Pat. No. 3,913,949 granted to C. A. Senatro on Oct. 21, 1975 and assigned to the same assignee as this patent application is exemplary of the coupling means of the present invention which constitutes an improvement thereof and which is incorporated herein by reference. The heretofore known coupling is characterized as having a conical metal-to-metal seal. Inherent in this type of seal is the necessity of applying a high level of torque to achieve a good positive seal from the metal-to-metal surfaces. This prohibits virtually no tolerance in the alignment of components. This inability to provide some misalignment manifests a rigid specification for the fuel carrying concentric tubes which have to either be made longer or require certain bends to avoid the excessive stresses.
I have found that by utilizing a composite rubber compound for the seal and eliminate the conical meta-to-metal sealing surfaces, I can obtain a higher degree of flexibility, allowing shorter tubes and eliminating the necessity of the steel construction of the coupling. This results in a less expensive device requiring less rigid design criteria.